Background: Implementation of a care bundle standardizing insertion, management, and removal practices to reduce infection related to central venous catheters (CVCs) used for hemodialysis was evaluated in a stepped wedge, cluster randomized controlled trial conducted at 37 Australian hospitals providing kidney services, with no reduction in catheter-related blood stream infection detected. This process evaluation explored the barriers, enablers, and unintended consequences of the implementation to explain the trial outcomes. Methods: Qualitative process evaluation using pre-post semistructured interviews with 38 (19 nursing and 19 medical) and 44 (25 nursing and 19 medical) Australian health professionals involved in hemodialysis CVC management. Analysis was guided by the process implementation domain of the Consolidated Framework for Implementation Research. Results: Key influences on bundle uptake were that clinicians were open to change that was evidence-based and driven by guidelines and had a desire to improve practice and patient outcomes. However, resistance to change in environments of low infection, working in silos of practice, and a need for individualized delivery of patient education created barriers to uptake. Unintended effects of increased costs and lack of interoperability of systems for data collection were reported. Because the trial was in progress at the time of qualitative data collection, perceptions of the bundle may have been influenced by the fact that practices of participants were being observed as a part of the trial. Conclusion: This national process evaluation revealed that health professionals who reported experiencing a benefit viewed the bundle positively. Those who already provided most of the recommended care or perceived that their patient population was not included in the research evidence that underpinned the interventions, resisted the implementation of the bundle. Potentially, formal change management processes using facilitation may improve implementation of evidence-based practice.